It has been suggested that in Alzheimer's disease, which has recently been increasing in prevalence, degeneration and dysfunction of cholinergic neurons are intimately related to memory disorder and lowering of intellectual activity Witehorse et al: Science, 215, 1237 (1982)!.
It has been reported that NGF can suppress the degeneration and dysfunction of centrally cholinergic neurons of the central nervous system due to fiber breakage Korsing et al: Neuroscience Lett., 66, 175 (1986)! and also can ameliorate maze learning disorder of aged rats and suppress atrophy of cholinergic neurons T. Shigeno et al: Igakuno Ayumi (Advances in drug), 145, 579 (1986)!. These show that NGF can serve as a drug for curing Alzheimers disease. Furthermore, it has been confirmed that NGF can prevent death of hippocampal neuronal cells after cerebral ischemia in gerbils, and it can be presumed that NGF is a useful drug for curing secondary disorder of cerebral ischemia.
On the other hand, it has been clarified that NGF functions to promote recovery of peripheral neuropathy and is a useful drug for curing the peripheral neuropathy. In addition to NGF, many biomolecules having the ability to maintain the survival and functioning of neuronal cells or showing an ability to remedy degeneration have been found, and they are now called neurotrophic factors. Thus, it can be presumed that these neurotrophic factors are useful drugs for curing central neuronal degeneration and peripheral neuropathy. All the biomolecules called neurotrophic factors including NGF are proteins. In using proteins as drugs for curing central nerve disorders, it can be presumed from their properties that intracerebroventricular administration must be carried out. Thus, there are still many practical problems.
Accordingly, a drug comprising a low molecular weight compound having the ability to act as a neurotrophic factor capable of more simple administration has been desired. Thus, an object of the present invention is to provide a novel compound having the ability to act as a neurotrophic factor.